Polyurethane foam is used in products in various fields due to its considerable pliability and cushioning properties. For example, it is used as cushioning materials, packing materials, gaskets and sealing materials of communication equipment, electronic equipment or the like. Since communications equipment, electronic equipment or the like tends to be lightweight and have a flat shape, sheet-like cushioning materials and packing materials are needed. Examples of sheet-like packing materials made of polyurethane foam include those described in the following Patent Literature 1 and 2.